Magnetic sensors are used in safety relevant applications, e.g. power steering. To achieve state-of-the art safety standards as described e.g. in ISO26262 automotive safety integrity levels are defined on the system level. The implementation of the required safety concept is broken down from the system and results in the implementation of safety mechanisms on the component level. The application consists of one or more magnetic sensors and an electronic control unit (ECU) that reads the output(s) from the sensor(s).
Today, the standard solution to achieve the required safety integrity level is to use redundancy, that is to place multiple (e.g. two) sensors in the application. A failure of one sensor can be detected in the ECU by a deviation of the output signals between the two sensors. The disadvantages are:                added (doubled) cost due to additional sensor;        In case of sensor failure, the system can not decide which sensor is failing and which is still in spec. This means that the system can not maintain normal operation. In case a system shut down is not a safe state, this may lead to the need for even more redundancy (e.g. three sensors) or other additional measures to identify the correct sensor output.        